Directional flow control valve with float and check valve structure

ABSTRACT

An improved directional flow control valve having a housing including an intake port, two motor ports adapted for connection to opposing sides of a hydraulic motor and an exhaust port for return of fluid from the hydraulic ram to the reservoir, the motor ports having check valve means interposed therein which normally preclude the return of fluid from said hydraulic ram to said valve housing, with control means within said valve housing for actuating the check valve means to selectively interconnect the intake port with either of the motor ports or to interconnect said motor parts with each other and the exhaust port to obtain a float condition within the hydraulic ram.

United States Patent [72] Inventor Vaughn A. Nelson Downers Grove, Ill. [21] Appl. No. 837,527 [22] Filed June 30, 1969 [45] Patented July 27, 1971 [7 3] Assignee International Harvester Company Chicago, 111.

[54] DIRECTIONAL FLOW CONTROL VALVE WITH FLOAT AND CHECK VALVE STRUCTURE 9 Claims, 2 Drawing Figs.

[52] US. Cl 137/5962 [51] lnt.Cl Fl6k 11/10 137/596,

[50] Field 0! Search... 625.25,625.67,625.69,596.2,596.13,636.l, 596.12, 596.13; 251/38 [56] References Cited 7 UNITED STATES PATENTS 2,572,705 10/1951 Edman l37/636.l

2.960,]11 1 H1960 Rose 137/596.l3 3,125,120 3/1964 Hasbany. 137/596.12 3,216,448 ll/l965 Stacey.... 137/5962 3,358,711 12/1967 Pruvot 251/38 X Primary Examiner-M. Cary Nelson Assistant Examiner-Robert J. Miller AtlorneyNoel G. Artman ABSTRACT: An improved directional flow control valve having a housing including an intake port, two motor ports adapted for connection to opposing sides of a hydraulic motor and-an exhaust port for return of fluid from the hydraulic ram to the reservoir, the motor ports having check valve means interposed therein which normally preclude the return of fluid from said hydraulic ram to said valve housing, with control means within said valve housing for actuating the check valve means to selectively interconnect the intake port with either of the motor ports or to interconnect said motor parts with each other and the exhaust port to obtain a float condition within the hydraulic ram. 1

INVENTOR NELSON PATENTED Jum 19?:

DIRECTIONAL F LOW CONTROL VALVE WITH FLOAT AND CHECK VALVE STRUCTURE BACKGROUND OF THE INVENTION This invention concerns a novel directional flow control valve primarily utilized for controlling a two-way acting hydraulic motor and incorporating therein check valve means within the porting of the flow control valve which will normally preclude the return of fluid from the hydraulic motor to the valve housing, and having control means for selectively actuating the check valve means to interconnect the intake port with either of the motor ports, or to interconnect the motor ports with each other and the exhaust port to obtain a float condition for the hydraulic motor.

Although the device may be advantageously utilized with any hydraulic motor including continuously rotating motors, rotary actuators or cylinders, it is particularly adaptable to use with double acting hydraulic rams used to control earth working implements. For example, it is often desireable to provide in the control valve for such motors a check valve means which normally precludes the leakage of fluid flow back from the hydraulic motor into the valve housing. Such check valves will fix" the position of the implement with respect to the vehicle, and leak back of the fluid as well as lowering of the implement is precluded. However the ability to obtain a float condition is also a desirable feature of a control valve in which condition the implement is completely free to maintain itself in a given relationship with the ground, automatically changing its vertical elevation according to the contour of the ground surface. The prior art fails to disclose a suitable structure to accomplish these inconsistent functions.

v SUMMARY OF THE INVENTION In order to provide a valve having the above identified characteristics, I have by unique structural relationship disclosed herein provided a directional flow control valve into which is incorporated provisions for both the check-type function and float-type functions of hydraulic ram system which may include either a single or double acting ram. Essentially, a pilot-operated poppet valve is incorporated into the motor ports of a valve housing, which may be actuated by a reciprocable spool so as to open alternatively to eliminate the check function in one of the motor ports, or to open the motor ports simultaneously so as to permit intercommunication between the two ends of a hydraulic ram. Accordingly it is an object of my invention to provide a novel and unique directional flow control valve incorporating both a check valve means, and a control means for said check valves in the same housing whereby they may be opened selectively to interconnect a motor port with an exhaust port and an intake port with another motor port or to merely interconnect both motor ports with each other and the exhaust port. A further object is to provide adirectibnal flow control valve of a type described which is extremely simple to manufacture, is inexpensive, and relatively simple to repair. Finally it is an object of the instant invention of the reciprocable spool type in which the spool is provided with camming surfaces sufficient to actuate the check valves so as to obtain flow to either end of the hydraulic motor, or to establish a flow condition through the valve interconnecting each end of the hydraulic motor.

DESCRIPTION OF THE DRAWINGS The manner in which these and other objects of the invention is obtained will be made clear by consideration of the following specification and claims when taken in conjunction with the accompanying drawings in which:

FIG. I is an elevational view taken in section through the longitudinal centerline of the valve; and

FIG. 2 is a sectional view taken along the lines 22 of FIG. I.

DETAIL DESCRIPTION As disclosed in the preferred embodiment of FIGS. 1 and 2, the unique advantages of my invention are incorporated into a valve for the well known closed center-type hydraulic system. Essentially, the invention includes a valve housing 10 having an elongated bore 11 extending therethrough with a spool 60 reciprocable within said bore. This elongated bore 11 has enlarged chambers therein denoted by the letters A, B, C, D, and E normally separated from one another by the normal diameter of the spool as clearly depicted. Reduced diameters of the spool 61, 66, and 69 are utilized to interconnect certain of these chambers with one another so as to permit fluid flow therebetween upon reciprocation of the spool 60.

The valve housing is also provided with an intake port 13, and two motor ports 15 and 17 which have associated cartridge units 32, 31 and 33 respectively to control flow to the chambers B, A, and C. As later explained, these cartridge units are actuated by reciprocation of the spool 60, but with respect to the control action of the spool alone, it should be noted that fluid energy from pump 9 is directed to intake port 13, through channel 14 to chamber B. Depending upon the direction of reciprocation of the spool 60, this fluid may be selectively delivered to chamber A, channel 16, and out motor port 15, or to chamber C, channel 18, and out motor port 17. Thus, assuming that the spool 60 is shifted to the right, fluid may flow from the intake port 13 through the channel 14, chamber B, chamber A, channel 16 to the motor port 15. Upon this reciprocation, (and subject to operation of pilot operated poppet valves hereinafter explained) fluid may be returned from the opposite end of the hydraulic ram through motor port 17, channel 18, chamber C, chamber E, and out an exhaust port 21. Upon reciprocation of the spool to the left, the opposite direction of fluid flow occurs with fluid from the hydraulic ram being exhausted via channel 16, chamber A, chamber D, and exhaust port 20.

With the invention as disclosed, this directional flow control is also dependent upon three cartridge-type pilot operated poppet valves 31, 32 and 33 which are suitably inserted into chambers 35, 36, and 37 by threaded means so as to intersect and further control the flow of fluid to and from the intake port 13 as well as each of the motor channels 16 and 18. Since each of these cartridge units 31, 32, and 33 are substantially identical in function and structure, reference may be had to FIG. 2 for a more complete description ofone of said units, in this case cartridge unit 32. A cylindrical housing 38 having radial apertures 39 and an open lower end 51 is threadably engaged in chamber 36 which is incorporated into the valve housing 10. When inserted the appropriate cartridge normally precludes flow of fluid into chambers A, B, and C from the respective ports 15, I3, and 17 as hereinafter explained. The lower end of the housing 38 is provided with a seat 40 for a poppet element 41. Within the poppet is a pilot-operated valve 45 having a stem 46 thereon and its lower end being conical so as to reciprocate within aperture 42 in the bottom of poppet 41 and seat itself against surface 43. A spring 47 biases this pilot member 45 against the seat 43, a reaction surface being provided by closure 48 of the cartridge unit which itself is held in place by a snapring as indicated. The unit 38 as well as the closure 48 is suitably provided with sealing elements where indicated. A small aperture 44 allows the pressurized fluid to communicate with the interior of poppet 41 and may pass freely through the fluted sections 50 of the pilot member 45 to act against the rear surface area of the pilot member 45 and poppet member 41. This pressurized fluid acting downwardly on the poppet together with the spring 47 normally maintains the poppets in a seated position. In view of this construction fluid energy acting against either the intake port 13, or either of the motor ports 15 and 17 will normally be precluded from flowing into the valve by this poppet member 41 which acts as a check valve unless opened.

In order to permit fluid to flow from a hydraulic ram through either of the motor ports 15 or 17, or to permit flow from the pump 9 into the valve housing 10, the pilot member 45 must be reciprocated upwardly. Suitable plungers 80, 81, and 82 reciprocating respectively within cylindrical openings 83, 84, and 85 serve as actuating elements to open each of the poppet valves 31, 32, or 33 upon movement of the spool 60 which is provided with cam surfaces (later explained) for effecting such reciprocation. Thus, as plunger unit 81 engages the stem 46 of the pilot member 45, this pilot member will be moved upwardly and fluid from the intake port 13 will flow through the apertures 39, the aperture 44 of the poppet member 41, aperture 42 and into channel 14. This flow of fluid will then reduce the force acting upon the upper face area of poppet member 41 and the pilot member 45 whereby the fluid pressure within intake port 13 acting upon surface area 49 of the poppet will cause the said poppet to further open. Further, as the plunger is withdrawn and the pilot element 45 is urged toward its seat 43 by resilient member 47, fluid pressure will again act upon the upper face of the pilot member 45 and the poppet 41 to cause the force acting on said members to overcome the force resulting from the intake pressure acting upon surface 49 and the valve will again close.

The reciprocation of the plungers 80, 81, and 82 is effected by reciprocating movement of the spool 60. Thus inclined cam surfaces 62, 63, 70, 71 and 72 which extend from the reduced diameters of the spool 61, 66, and 69 will engage the plungers to cam them upwardly upon appropriate shifting of the spool 60. Once the plungers have been shifted upwardly, a holding surface 64, 65, 67, 68, or 73 will operate to hold the plungers in their upward position. The cam surfaces 63, 70, 71, and 72 should be so positioned that upward movement of plunger 81 will simultaneously cause upward reciprocation of the plunger within the port to which fluid is to be admitted to bore 11 leaving the opposite poppet to be opened by fluid flow. For example, if fluid is to be directed out of port 15 and returned to the exhaust 21 via port 17, movement to the right of spool 60 should open the poppets of cartridges 32 and 33 with fluid pressure opening poppet of cartridge 31.

As is well known in the art, I have additionally provided a centering mechanism 100 which will normally maintain the spool 60 in the neutral position in which all of the poppet valves are closed. This centering mechanism comprises a housing 101 threadably and sealingly attached to the valve housing as clearly indicated, and a compression spring 102 is employed in the housing 101 to act against suitable washers 103 or 104 maintained in place by abutment 108 and bolt 105 as disclosed so as to increase the bias of the spring at any time the spool 60 is reciprocated in either direction. The bolt 105 acting against washer 104 extends into the spool 60 to connect the spring bias forces to the spool. A seal assembly 107 disposed about spool 60 precludes leakage from the centering mechanism.

Also disclosed within the valve housing but not vital to the instant invention is a unique flow sensitive detent mechanism, more specifically disclosed in my copending application, Ser. No. 840,647 tiled July I0, 1969. This mechanism comprises a spring biased flow responsive device within preferably the intake porting consisting of intake 13 and channel 14. Thus, a spring 91 is interposed between a disc washer 93, and a flow responsive cup-shaped element 90. Consequently, if the spool 60 is reciprocated either to the right or to the left, the plunger 81' will be caused to move upwardly and seat itselfeither in detent position 67 or 68. This upward reciprocation of plunger 81 then opens the pilot member 45 ofcartridge 38, and due to a pressure unbalance, the poppet 41 will also be caused to open. Flow from the variable displacement pump 9 will then pass through the cartridge housing 38 and impinge against the upper surface of cup-shaped member 91 causing same to move downwardly to an extent whereby the fluid may pass through several vents 94 in the sidewalls of the cup 90. This downward movement of member 90 in turn increases the bias of spring 91 which will act against washer 93, and an enlarged diameter of plunger 81 which has been elevated by either cam surface 70 or 71. Preferably, the bias of spring 91 together with the detent holding surfaces which include the bottom of plunger 81 and the detent surfaces 67 and 68 are sufficient to overcome the opposing bias of the centering mechanism 100 which would otherwise return the spool to its neutral position.

Assuming that the spool is shifted to the right, the plunger 81 is reciprocated upwardly to open the cartridge 32, and the bottom of plunger 81 enters detent 67 and is held in that position by the flow sensitive cup-shaped member 90 increasing the bias of spring 91. Thus, fluid will flow through channel 14, chamber B, chamber A, and out channel 16 and motor port 15 and as long as such fluid continues to flow, cup-shaped member 90 will be in its downward position so as to enable the detent mechanism to overcome the biasing force of the centering mechanism 100, but as soon as flow ceases and the hydraulic ram has travelled to the end of its stroke, the cupshaped member 90 will return to its original position with the centering mechanism 100 returning the spool 60 to its neutral position. Since only a resilient bias is imposed on spool 60, its position remains subject to manual control which may override the flow imposed bias.

Utilization of the poppet valves within the motor ports accomplishes a principal object of my invention and results in a unique advantage in that a system is produced whereby check valves may be incorporated into a directional flow control valve and yet obtain a float condition for an associated hydraulic motor. As previously mentioned, the cartridges 31, 32, and 33 preclude the flow of fluid from either of the motor ports or the intake port into the elongated bore 11 ofthe valve housing 10. Thus, while flow alone will cause the valves to open to supply fluid to either end of a hydraulic ram, positive reciprocating movement ofthe spool must be made in order to permit flow in the opposite direction. Such is the preferred way of precluding leakage from a hydraulic motor back through the valve. However, in many hydraulic ram applications, it is often desirable to obtain a float condition for the ram in which fluid will be free to flow from one end of the ram to the opposite end of the ram or to the reservoir. Thus, in the instant application, if the spool is reciprocated to the far right and held in such position, plunger 81 will enter a reduced diameter 74 of the spool in which poppet 45 is closed and plungers and 82 will be cammed upwardly by cam surfaces 62 and 72 and rest upon holding surfaces 64 and 73. In this condition, the normal diameters of the spool are entirely within the enlarged chambers and fluid may flow between motor port 17 and motor port 15, (both of the poppets being opened by the raised position of the plungers 80 and 82) and exhaust port 21. In order to hold the spool in the reciprocated float position, a tensioned garter spring 106 will engage reduced diameter 75 to overcome the bias of centering mechanism 100 and maintain a float condition.

MODE OF OPERATION The above-described structure when operated will result in several unique operating capabilities for a hydraulic directional flow control valve. As the spool is shifted to the right, plunger 81 is elevated into detent position 67 causing the pilot-operated poppet 41 to open and fluid from the variable displacement pump 9 acts against the flow responsive element to overcome the bias of the centering mechanism 100. The spool will maintain this position as long as fluid flows in a manner to maintain the increased spring bias of resilient means 91 and will flow into chambers B, A, and out motor port 15, the flow being sufficient to open the poppet. However, plunger 82 is also reciprocated at this time to open the check of poppet valve of cartridge 33 and fluid is exhausted from one end of the hydraulic cylinder into the motor port 17, channel 18, chambers C, E, and back to a reservoir through exhaust port 21.

Reciprocation in the opposite direction will merely reverse flow to and from the hydraulic ram. However, if the spool is reciprocated to its rightmost position it should be observed that plunger element 81 will seat itself in the reduced diameter 74 of the spool 60 which is insufficient to open poppet valve 41 while both plungers 80 and 82 will be reciprocated upwardly by cam surfaces 62 and 72 and onto holding surfaces 64 and 73. At this time fluid may clearly communicate between chambers C, B, A, and E and thus motor ports and 17 thereby placing the hydraulic motor into a float condition. Thus, with fluid flowing freely between motor ports 15 and 17, the hydraulic ram is free to extend or contract depending on external forces, and if for example the ram is utilized with an implement attached to a vehicle, the implement may freely alter its vertical position to ride freely across varying terrain surfaces. It should be immediately appreciated that the check and float functions and the inventive subject matter may easily be incorporated in a valve having only one motor part.

It should be readily appreciated that my instant invention discloses several unique structural and operating characteristics. It may easily be adopted to be incorporated into an open centered-type valve structure and the flow responsive means herein disclosed might appropriately he placed within any of the ports, including the exhaust ports as well as either of the motor ports. By comparing the strength of the opposing biasing members, the valve will always be maintained in its proper position according to desires of the operator. Most importantly, it should be appreciated that if high operating pressures are created by heavy loads, my particular invention will overcome the disadvantages of the prior art in that the detent mechanism will positively hold until the ram has reached the end of its stroke. The entire system being substantially insensitive to high pressures. Finally. a directional flow control valve has been disclosed in which check valves may be used and yet a float condition may be obtained. The interaction between cam surfaces accurately positioned on a spool and the check valves so as to prevent leak back from a motor and to selec tively control the exhaust of fluid from one side of the motor or to create a float condition provides a unique manufacturing solution to achieve desirable functional capabilities. As specifically indicated by the fact that the subcomponents herein disclosed may be incorporated into either an open or closed center system, it should be well appreciated that the present embodiment is merely illustrative and not restrictive.

What I claim is:

1. An improved directional flow control valve comprising:

a. a housing having an intake port and two motor ports adapted for connection to opposing ends of a hydraulic ram and an exhaust port for return of fluid from the hydraulic ram to a reservoir;

b. check valve means interposed in said motor ports and said intake port which normally preclude return of fluid from said hydraulic ram to said valve housing;

or control means within said valve housing and effective to actuate said check valve means for selectively interconnecting saidintake port with either of said motor ports and the other motor port with an exhaust, or interconnecting said motor ports to obtain a float condition for the hydraulic ram.

. An apparatus as defined in claim 1 in which said spool means comprises a spool reciprocable within said valve housing.

3. An apparatus as defined in claim 2 in which said control means comprises check valve-actuating means interposed between said spool and said check valve means for actuation by said spool to achieve interconnection between the intake port and either of said motor ports or interconnection between said motor ports.

4. An apparatus as defined in claim 3 in which said control means comprises cam surfaces on said spool, and said check valve actuating means comprises reciprocable plungers reciprocated by said cam means to open said valves.

5. In a directional flow control valve having a housing, an intake port and two motor ports, an exhaust port and a spool within said housing for interconnecting said intake ort with one of said motor ports and the other motor port wit said exhaust port, the improvement comprising:

a. check valve means within said motor ports and exhaust port for normally precluding fluid flow from a hydraulic ram to said valve housing or from said intake port to said spool;

b. actuating means interposed between said check valve means and said spool for selectively opening said check valves upon reciprocation of said spool; and

. at least three cam means on said spool whereby flow may be directed from either of said ends of said hydraulic ram to said exhaust port or to interconnect said motor ports and exhaust port,

An improved directional flow control valve comprising:

a housing,

an elongated bore within said housing, an intake port two motor ports and an exhaust port on said housing, each having a channel communicating with said elongated bore,

. poppet valve means disposed within said channels for normally precluding fluid flow from said intake and motor ports to said elongated bore,

e. spool means reciprocable within said elongated bore, and

. control means disposed between said poppet valve means and said spool for actuating said poppet valves upon reciprocation of said spool.

7. An apparatus as defined in claim 6 in which:

. said control means comprises plunger elements interconnecting said spool and said poppet valves, and

. cam means disposed upon said spool which are effective to reciprocate said plunger elements upon reciprocation ofsaid spool.

. An apparatus as defined in claim 7 in which:

said camming surfaces are so disposed upon said spool so as to selectively actuate the poppet valve in said intake port and the poppet valve in one motor port or to actuate solely said poppet valves in said motor ports.

An improved directional control valve comprising:

a housing,

. an elongated bore within said housing,

an intake port, at least one delivery port adapted for connection to a hydraulic ram, and an exhaust port, each port being in communication with said elongated bore,

(1. poppet valve means disposed within said delivery port and said intake port for normally precluding flow from such ports to said elongated bore,

e. spool means reciprocable within said elongated bore, and

f. control means disposed between said poppet valve means and said spool for selectively permitting fluid flow from said intake port to said motor port or from said motor port to said exhaust port.

a w s? poo 

1. An improved directional flow control valve comprising: a. a housing having an intake port and two motor ports adapted for connection to opposing ends of a hydraulic ram and an exhaust port for return of fluid from the hydraulic ram to a reservoir; b. check valve means interposed in said motor ports and said intake port which normally preclude return of fluid from said hydraulic ram to said valve housing; c. control means within said valve housing and effective to actuate said check valve means for selectively interconnecting said intake port with either of said motor ports and the other motor port with an exhaust, or interconnecting said motor ports to obtain a float condition for the hydraulic ram.
 2. An apparatus as defined in claim 1 in which a. said spool means comprises a spool reciprocable within said valve housing.
 3. An apparatus as defined in claim 2 in which said control means comprises check valve-actuating means interposed between said spool and said check valve means for actuation by said spool to achieve interconnection between the intake port and either of said motor ports or interconnection between said motor ports.
 4. An apparatus as defined in claim 3 in which said control means comprises cam surfaces on said spool, and said check valve actuating means comprises reciprocable plungers reciprocated by said cam means to open said valves.
 5. In a directional flow control valve having a housing, an intake port and two motor ports, an exhaust port and a spool within said housing for interconnecting said intake port with one of said motor ports and the other motor port with said exhaust port, the improvement comprising: a. check valve means within said motor ports and exhaust port for normally precluding fluid flow from a hydraulic ram to said valve housing or from said intake port to said spool; b. actuating means interposed between said check valve means and said spool for selectively opening said check valves upon reciprocation of said spool; and c. at least three cam means on said spool whereby flow may be directed from either of said ends of said hydraulic ram to said exhaust port or to interconnect said motor ports and exhaust port.
 6. An improved directional flow control valve comprising: a. a housing, b. an elongated bore within said housing, c. an intake port two motor ports and an exhaust port on said housing, each having a channel communicating with said elongated bore, d. poppet valve means disposed within said channels for normally precluding fluid flow from said intake and motor ports to said elongated bore, e. spool means reciprocable within said elongated bore, and f. control means disposed between said poppet valve means and said spool for actuating said poppet valves upon reciprocation of said spool.
 7. An apparatus as defined in claim 6 in which: a. said control means comprises plunger elements interconnecting said spool and said poppet valves, and b. cam means disposed upon said spool which are effective to reciprocate said plunger elements upon reciprocation of said spool.
 8. An apparatus as defined in claim 7 in which: a. said camming surfaces are so disposed upon said spool so as to selectively actuate the poppet valve in said intake port and the poppet valve in one motor port or to actuate solely said poppet valves in said motor ports.
 9. An improved directional control valve comprising: a. a housing, b. an elongated bore within said housing, c. an intake port, at least one delivery port adapted for connection to a hydraulic ram, and an exhaust port, each port being in communication with said elongated bore, d. poppet valve means disposed within said delivery port and said intake port for normally precluding flow from such ports to said elongated bore, e. spool means reciprocable within said elongated bore, and f. control means disposed between said poppet valve means and said spool for selectively permitting fluid flow from said intake port to said motor port or from said motor port to said exhaust port. 